Revenue - Disaggregated Revenue (Details) - USD ($) $ in Millions	1 Months Ended	2 Months Ended	3 Months Ended
	Feb. 09, 2021	Mar. 31, 2021	Mar. 31, 2020
Disaggregation of Revenue [Line Items]
Total revenues and other	$ 260	$ 880	$ 2,525
Oil, natural gas and NGL revenue
Disaggregation of Revenue [Line Items]
Total revenues and other	398	553	894
Marketing
Disaggregation of Revenue [Line Items]
Revenues			662
Total revenues and other	239	277	724
Other marketing revenue
Disaggregation of Revenue [Line Items]
Total revenues and other			62
Appalachia
Disaggregation of Revenue [Line Items]
Revenues	119	163	175
Gulf Coast
Disaggregation of Revenue [Line Items]
Revenues	53	70	85
South Texas
Disaggregation of Revenue [Line Items]
Revenues	122	164	328
Brazos Valley
Disaggregation of Revenue [Line Items]
Revenues	71	108	180
Powder River Basin
Disaggregation of Revenue [Line Items]
Revenues	33	48	90
Mid-Continent
Disaggregation of Revenue [Line Items]
Revenues			36
Oil | Oil, natural gas and NGL revenue
Disaggregation of Revenue [Line Items]
Total revenues and other	179	234	539
Oil | Marketing
Disaggregation of Revenue [Line Items]
Revenues			508
Total revenues and other	141	162	569
Oil | Other marketing revenue
Disaggregation of Revenue [Line Items]
Total revenues and other			61
Oil | Appalachia
Disaggregation of Revenue [Line Items]
Revenues	0	0	0
Oil | Gulf Coast
Disaggregation of Revenue [Line Items]
Revenues	0	0	0
Oil | South Texas
Disaggregation of Revenue [Line Items]
Revenues	92	117	277
Oil | Brazos Valley
Disaggregation of Revenue [Line Items]
Revenues	67	89	172
Oil | Powder River Basin
Disaggregation of Revenue [Line Items]
Revenues	20	28	68
Oil | Mid-Continent
Disaggregation of Revenue [Line Items]
Revenues			22
Natural Gas | Oil, natural gas and NGL revenue
Disaggregation of Revenue [Line Items]
Total revenues and other	196	290	320
Natural Gas | Marketing
Disaggregation of Revenue [Line Items]
Revenues			124
Total revenues and other	78	97	125
Natural Gas | Other marketing revenue
Disaggregation of Revenue [Line Items]
Total revenues and other			1
Natural Gas | Appalachia
Disaggregation of Revenue [Line Items]
Revenues	119	163	175
Natural Gas | Gulf Coast
Disaggregation of Revenue [Line Items]
Revenues	53	70	85
Natural Gas | South Texas
Disaggregation of Revenue [Line Items]
Revenues	15	28	31
Natural Gas | Brazos Valley
Disaggregation of Revenue [Line Items]
Revenues	2	15	4
Natural Gas | Powder River Basin
Disaggregation of Revenue [Line Items]
Revenues	7	14	15
Natural Gas | Mid-Continent
Disaggregation of Revenue [Line Items]
Revenues			10
NGL | Oil, natural gas and NGL revenue
Disaggregation of Revenue [Line Items]
Total revenues and other	23	29	35
NGL | Marketing
Disaggregation of Revenue [Line Items]
Revenues			30
Total revenues and other	20	18	30
NGL | Other marketing revenue
Disaggregation of Revenue [Line Items]
Total revenues and other			0
NGL | Appalachia
Disaggregation of Revenue [Line Items]
Revenues	0	0	0
NGL | Gulf Coast
Disaggregation of Revenue [Line Items]
Revenues	0	0	0
NGL | South Texas
Disaggregation of Revenue [Line Items]
Revenues	15	19	20
NGL | Brazos Valley
Disaggregation of Revenue [Line Items]
Revenues	2	4	4
NGL | Powder River Basin
Disaggregation of Revenue [Line Items]
Revenues	$ 6	$ 6	7
NGL | Mid-Continent
Disaggregation of Revenue [Line Items]
Revenues			$ 4